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Biomedical subjects

K Yonenobu

Publications and source records attributed to K Yonenobu.

At least 55 records · Page 3Linked to original sources
PubMed1995

Natural course of cervical spine lesions in rheumatoid arthritis.

STUDY DESIGN: This study analyzed the natural course of cervical spine involvement in rheumatoid arthritis by serial radiographs. OBJECTIVES: The purpose was to determine the pattern of progression of cervical spine lesions in rheumatoid arthritis and predictors for the extent of progression. SUMMARY OF BACKGROUND DATA: Subluxation frequently occurs as a result of rheumatoid involvement of the cervical spine. It may be severe in patients with mutilans deformities in the hands and feet. The extent of progression in a given patient is still unpredictable. METHODS: Serial cervical radiographs in 49 patients with rheumatoid arthritis were analyzed. The extent of progression was evaluated by rheumatoid arthritis subset defined previously, which reflected the final extent of joint erosion in this systemic disease and could be roughly classified during early stages of the disease. RESULTS: In the upper cervical spine, reducible anterior atlantoaxial subluxation occurred first. Vertical subluxation of the axis appeared next. Irreducible change of preceding anterior atlantoaxial subluxation was a sign of the start of vertical subluxation. In subaxial lesion, subluxation occurred less frequently (22.4%) than upper cervical lesion (77.6%). The extent of progression was different with the rheumatoid arthritis subset. In the upper cervical spine, none of the subset with least erosive disease developed vertical subluxation, whereas 52% of the subset with more erosive disease and 88% of the subset with mutilating disease advanced to vertical subluxation. The extent of progression was well correlated with the number of joints with erosion. Subaxial subluxation was often seen and became irreducible in mutilating disease and more erosive disease, but not in least erosive disease. CONCLUSIONS: A progressive pattern of the upper cervical subluxations was clarified. That is, upper cervical lesions progressed from reducible anterior atlantoaxial subluxation to irreducible anterior atlantoaxial subluxation with vertical subluxation. This extent of progression was different with the rheumatoid arthritis subset, which was also related to the development of subaxial subluxation. The most aggressive arthritis classification, a subset with mutilating disease, had the more severe subluxation in both upper and subaxial cervical spine.

Adolescent↗
PubMed1995

Orthopaedic management of spinal metastases.

Spinal metastases result in severe spinal pain, neurologic deficits, or both. These symptoms usually are caused by spinal instability, in which conservative therapy can have no effect, and surgical treatment is required to restabilize the destroyed spinal segments. Surgical indications are instability of the spine, pain and/or paresis resistant to radiation therapy, acute progressing paresis, and unknown histologic diagnosis. There are 2 surgical approaches for vertebral metastases: prosthetic replacement and posterior stabilization. Single or 2 consecutive diseased vertebrae should be treated with replacement surgery. In this series, excellent surgical outcome was attained with this procedure, and surgical benefit was maintained until the terminal stage of each patient. Multiple vertebral metastases are treated with posterior stabilization using various instrumentation systems that provide rigid stabilization. To choose the most appropriate procedure for each patient, the local condition of the lesion and general status of the patient, including prediction of life expectancy, should be evaluated fully. Spinal metastases develop early and are not terminal events. Therefore, not only palliative treatment but also surgical intervention should be considered for spinal metastases when indicated.

Humans↗
PubMed1995

The application of Diapason spinal fixator device: a comparison with the Steffee VSP plate.

Twenty-five consecutive patients who had a variety of lumbar disorders and who underwent lumbar spinal fusion using the Diapason fixator were followed for a mean period of 20 months. The operations included 16 posterior lumbar interbody fusion (PLIF), 7 posterolateral fusion (PLF), and 2 combined PLIF and PLF (PLIF/PLF). As a control group, 38 patients undergoing PLIF using a Steffee VSP plate (VSP) were followed for a mean period of 24 months. There were no significant differences between the two groups regarding the operation time, blood loss, and improvement of preoperative symptoms. However, incidence of incomplete bony union and radiolucent zone around the screws were higher in the Diapason group than in the VSP group. Our study suggests that there was a possibility of insufficient rigidity of screw-rod fixation in the Diapason system.

Adult↗
PubMed1994

Magnetic stimulation of biceps after intercostal cross-innervation for brachial plexus palsy. A study of motor evoked potentials in 25 patients.

We studied the motor evoked potentials (MEP) in the biceps of 25 patients with traumatic brachial plexus palsy from root avulsion after cross-innervation by intercostal nerves. We used transcranial, transcervical and transthoracic magnetic stimulation at 8 to 235 months (mean 51) after transfer of intercostal nerves to the musculocutaneous nerve. Biceps strength recovered to MRC grade 2 in eight patients, grade 3 in three and grade 4 in 14. The mean latency of the MEP in the normal biceps on transcranial stimulation was 12.5 +/- 1.3 ms and on transcervical stimulation 6.3 +/- 1.1 ms. After intercostal reinnervation the mean latency on transcranial stimulation was 21.7 +/- 4.5 ms and on transthoracic stimulation 11.6 +/- 3.8 ms. The latency of the biceps MEP after reinnervation by intercostal nerves on transcranial and transthoracic magnetic stimulation correlated well with the duration of follow-up and the latency of the MEP on transthoracic magnetic stimulation correlated significantly with muscle power.

Adolescent↗
PubMed1993

Elevated plasma fibronectin concentrations in patients with ossification of the posterior longitudinal ligament and ossification of the ligamentum flavum.

Fibronectin is a glycoprotein involved in a wide variety of cellular activities, including the development of bone tissues. To study the relevance of fibronectin to the development of ossification of the posterior longitudinal ligament (OPLL) and ossification of the ligamentum flavum (OLF), plasma fibronectin concentrations in 30 consecutive patients with OPLL or OLF and 20 age-and-sex-matched control subjects were measured with an immunonephelometric method. Plasma fibronectin concentrations were significantly elevated in the patients with OPLL or OLF, independently of associated endocrinologic abnormalities, when compared with the control subjects. Because fibronectin is one of the essential factors in endochondral ossification, it is probable that the higher fibronectin concentration in plasma acts as a promoter of the development of OPLL and OLF.

Causality↗
PubMed1992

Ossification of the ligamentum flavum induced by bone morphogenetic protein. An experimental study in mice.

Ossification of the ligamentum flavum and secondary spinal-cord compression were produced experimentally in mice by implanting bone morphogenetic protein (BMP) in the lumbar extradural space. The ligamentum flavum became hypertrophied and ossified, and protruded into the spinal canal. The thickness of the ossified ligament increased gradually with time, leading to compression and deformation of the spinal cord which showed various degrees of degeneration. Demyelination occurred in the posterior and lateral white columns and neuronal loss or chromatolysis in the grey matter. The pathological findings in the experimental animals closely resemble those found in the human disease and suggest that BMP may be a causative factor of ossification of the ligamentum flavum in man. This experimental model may be useful for the study of myelopathy caused by gradual spinal-cord compression.

Animals↗
PubMed1992

Laminoplasty versus subtotal corpectomy. A comparative study of results in multisegmental cervical spondylotic myelopathy.

A comparative study of surgical results was used to determine the treatment of choice for multisegmental cervical spondylotic myelopathy. Forty-one patients who received subtotal corpectomy and strut grafting (SCS) and forty-two undergoing laminoplasty were followed up for at least 2 years after surgery. Regarding factors known to affect surgical prognosis (age at surgery, duration of symptoms, severity of neurologic deficit, anteroposterior canal diameter, transverse area of the cord at the site of maximum compression, number of levels involved), the two groups were statistically comparable with each other. The severity of neurologic deficits was assessed by the Japanese Orthopaedic Association scale. Results were evaluated in terms of postoperative score and recovery rate. The difference between the recovery rate and final score between the two groups was not statistically significant. Surgical complications were more frequent in the subtotal corpectomy and strut grafting group than in the laminoplasty group. The most frequent complications encountered in the subtotal corpectomy and strut grafting group were related to bone grafting. Spinal alignment worsened in six patients of the laminoplasty group, but none of them suffered from neurologic deterioration. Another disadvantage of subtotal corpectomy and strut grafting was the longer postoperative period of bed rest needed to secure graft stability. We conclude that laminoplasty should be the treatment of choice for multisegmental cervical spondylotic myelopathy when neurologic results, incidence of complications, and postoperative treatment are taken into consideration.

Aged↗
PubMed1991

Breast cancer with bone-only metastases. Visceral metastases-free rate in relation to anatomic distribution of bone metastases.

The medical records of 82 patients with breast cancer with bone-only metastases were reviewed. According to the distribution of the metastases by bone scan at the time they were first documented, the patients were divided into three groups: Group A (patients who had bone metastases exclusively cranial to the lumbosacral junction), Group B (patients who had bone metastases exclusively caudal to the junction), and Group C (patients who had bone metastases both cranial and caudal to the junction). Group A had a significantly higher visceral metastases-free rate than Groups B or C. Serial bone scans and radiographs of Group A patients revealed that bone lesions cranial to the junction rarely developed into visceral metastases and that bone lesions extending caudal to the junction frequently developed into visceral metastases. These results indicate that the presence of bone metastases caudal to the lumbosacral junction is predictive of visceral metastases.

Adult↗
PubMed1991

Thoracic myelopathy caused by ossification of the ligamentum flavum. Clinicopathologic study and surgical treatment.

The authors reviewed 14 patients with thoracic myelopathy caused by ossification of the ligamentum flavum (OLF). The predominant locality of symptomatic OLF was at the thoracolumbar junction, particularly at T10-11 followed by T11-12. At the level of the thickest OLF in each patient, there were three types of OLF from computed tomography and operative findings: a lateral type in 3 patients, diffuse in 8, and thickened nodular in 3. The diagnosis of OLF-related thoracic spinal canal stenosis was best made by enhanced computed tomography. Histologic study revealed that the developmental mode of OLF was mainly endochondral ossification. Numerous fibrocartilaginous cells were found in the increased and swollen collagen fibers forming the hypertrophic ligamentum flavum (HLF). Ossification extended along the superficial layer of HLF. The size or extension of OLF was relevant to the corresponding diathesis of spinalhyperostosis. Results of laminectomy for OLF were poor because of the high occurrence of complications early on or later deterioration. Therefore, laminoplasty is recommended as a successful procedure for OLF-related thoracic myelopathy, avoiding further local mechanical stress due to tensile force.

Female↗
PubMed1991

Os odontoideum with posterior atlantoaxial instability.

Nine patients who had os odontoideum with posterior atlantoaxial instability are reviewed. Three parameters were measured on the lateral radiographs: the distance from the os odontoideum to the spinous process of the axis in extension (Dext), the distance from the os odontoideum to the posterior arch of the atlas (Datl), and the degree of instability (Inst). Patients were classified into four groups: Group I, local symptoms (N = 3); Group II, transient myelopathy (N = 0); Group III, progressive myelopathy (N = 6); and Group IV, cerebral symptoms (N = 0). The development of cervical myelopathy was not related to degree of instability but to distance from the os to the spinous process of the axis (Dext). Dext was more than 16 mm in Group I and less than or equal to 16 mm in Group III. Five of six patients in Group III underwent myelography. Based on myelographic findings, Group III was further subdivided into two groups, Group IIIA (N = 2) and Group IIIB (N = 3), according to the following characteristics: In Group IIIA, the distance from the os to the posterior arch of the atlas was more than 13 mm, and the spinal cord was impinged between the os odontoideum and the lamina of the axis in extension and reduced in flexion. In Group IIIB, Datl was less than or equal to 13 mm, and the spinal cord was compressed at the level of the atlas during flexion and extension. Stenotic Datl of 13 mm or less specifically defined severe cervical myelopathy. Surgical treatment for cervical myelopathy in os odontoideum with posterior instability is suggested as follows: in the absence of canal stenosis of the atlas (Group IIIA), atlantoaxial fusion in a reduced position is indicated; when associated with canal stenosis of the atlas (Group IIIB), laminectomy of the atlas followed by occiput-to-C2 arthrodesis is indispensable.

Adolescent↗
PubMed1991

Cineradiographic motion analysis of atlantoaxial instability in os odontoideum.

Cineradiography was used to study six patients with os odontoideum. Atlantoaxial kinematics was analyzed with the relative motion of the atlas on the axis. In all cases, the tracing of the anterior arch was straight in the sagittal plane, whereas the posterior arch moved in two different configurations: straight and S-shaped. In cases of S-shaped configurations, the anterior translation occurred in the neutral position. Such translation could threaten the stability of the atlantoaxial complex fixed with posterior wiring because circumferential wires allow the laminas to rotate in the sagittal direction. In patients with os odontoideum, pathomechanics of the atlantoaxial joint should be examined with cineradiography in order biomechanically to determine the soundest fixation.

Adolescent↗
PubMed1991

Experimental cervical spondylosis in the mouse.

A reproducible experimental model of cervical spondylosis in mice was established by means of detachment of the posterior paravertebral muscles from the vertebrae and resection of the spinous processes along with the supraspinous and interspinous ligaments. Mechanical instability in the cervical spine elicited by this surgical intervention accelerated the process of intervertebral disc degeneration, and when extended over a 6-12-month period, induced cervical spondylosis in the mice. The pathologic findings in the cervical intervertebral discs of this experimental model varied: proliferation of cartilaginous tissue and fissures in the anulus fibrosus, shrinkage of the nucleus pulposus, herniation of disc material, and osteophyte formation. The availability of this experimental model should be valuable for biochemical and biomechanical understanding of the pathogenesis of cervical spondylosis.

Animals↗
PubMed1991

Neurologic complications of surgery for cervical compression myelopathy.

Neurologic complications resulting from surgery for 384 cases of cervical myelopathy (cervical soft disc herniation, spondylosis, ossification of the posterior longitudinal ligament) were reviewed. Surgical procedures performed included 134 anterior interbody fusions (Cloward or Robinson-Smith technique), 70 subtotal corpectomies with strut bone graft, 85 laminectomies, and 95 laminoplasties. Twenty-one patients (5.5%) sustained neurologic deterioration related to surgery. The deterioration was classified into two types on the basis of the neurologic signs observed: deterioration of spinal cord function or of nerve root function. Manifestations of the former varied from weakness of the hand to tetraparesis. Paralysis of the deltoid and biceps brachii muscles was an exclusive feature of deterioration in the nerve root group. Causes of this paralysis included malalignment of the spine related to graft complications, and a tethering effect on the nerve root following major shifting of the spinal cord after decompression. The causes of deterioration of the cord function included spinal cord injury during surgery, malalignment of the spine associated with graft complication, and epidural hematoma.

Cervical Vertebrae↗
PubMed1990

Lateral rhachotomy for thoracic spinal lesions.

Capener's "Lateral Rhachotomy" was modified by additional excision of the pedicle, articular facets, part of the lamina, and a posterior half of the vertebral bodies on one side through a transpleural approach to the thoracic spine, and a retroperitoneal approach to the lumbar spine. The aim was to excise a space-occupying lesion, which exists in front of the thoracic or lumbar spinal cord, safely. This modification enable the authors to expose more than 50% of the spinal canal, and decompress it from its anterior, lateral, and posterior compressing mass. The utmost important point of this procedure is the excision of the lesion under the direct visualization of the dura. In ossification of the posterior longitudinal ligament (OPLL), the dura is usually indented by the thick bony mass, and the lesion extends over a few segment with adhesion. Using "Modified Lateral Rhachotomy," it was possible to explore three or four vertebral levels in continuity through the same skin incision. In the present report, the authors described their "Modified Lateral Rhachotomy" procedure, and reviewed the case material.

Female↗